This invention is directed to the encapsulation of photoluminescent silica nanoparticles in a coating matrix.
In the prior application SN 08/398,268, there is described a novel form of silica having a three-dimensional web-like nanoparticle morphology. The material is prepared as a low density powder which exhibits strong visible photoluminescence when excited with ultraviolet (UV) light.
However, for useful applications of the photoluminescent effect, the powder form of silica nanoparticles is not convenient. To solve this problem, we have shown that these silica nanoparticles can be encapsulated in a curable silicone composition, and that the mixture can then be cast as a coating on a substrate (i.e., glass or a silicon wafer), without loss of the photoluminescent properties of the silica nanoparticle structure. Such coatings are useful in image intensifiers that convert soft X-rays to visible light, or in detectors of UV light rays for beam positioning.